This invention relates to a sound generating system and, more particularly, to a sound generating system for producing sound from vibrations in a musical instrument through a natural microphone simulation.
A stringed instrument such as, for example an acoustic guitar is used for ensemble as well as solo. The solo or ensemble may be recorded through a microphone. While the acoustic guitar is being ensembled with other musical instruments, the acoustic guitar sound is gathered through the microphone together with the other sorts of sound, and the acoustic guitar sound and the other sorts of sound are converted to an electric signal, and are mixedly stored in a suitable recording medium. It is impossible to record only the acoustic guitar sound through the microphone during the ensemble. If the guitar sound is to be selectively recorded during the ensemble, the vibrations of strings are directly converted through a pickup unit, which is attached to the acoustic guitar to an electric signal. A piezoelectric converting element is preferable for the direct conversion from the mechanical vibrations to electric energy, because the electric signal from the piezoelectric pickup unit is easy processed for the volume control and feedback control. The electric signal is equalized and amplified through a suitable amplifier, and is supplied to a speaker system. The speaker system converts the electric signal to reproduced guitar sound.
Although the electric signal is directly converted from the vibrations of strings, the listener feels the reproduced guitar sound different from the acoustic guitar sound. The listener expresses the reproduced guitar sound as xe2x80x9cnot so rich as the acoustic guitar soundxe2x80x9d. This is because of the fact that the electric signal merely represents the vibrations of the strings. In other words, the electric signal does not contain signal components representative of the reverberation.
It is proposed to process the electric signal for making the reproduced guitar sound approximate to the acoustic guitar sound. The prior art signal processing system simulates the reverberation in the resonator of the acoustic guitar as well as the sound directly produced from the vibrations of the plucked string. The sound directly produced from the vibrations of the plucked string is hereinbelow referred to as xe2x80x9cdirect soundxe2x80x9d. The prior art signal processing system includes a signal processing unit assigned to the direct sound. The signal processing unit has a delay circuit, and produces an electric signal representative of the direct sound through the delay circuit.
Although the prior art signal processing system produces an audio signal representative of a reproduced sound with the reverberation, sharp dips periodically take place in the frequency characteristics of the audio signal so that a certain frequency band is unnaturally emphasized. The certain frequency band influences the timbre of the reproduced sound, and the listener feels the reproduced sound unnatural.
It is an important object of the present invention to provide a sound generating system, which produces sound approximate to acoustic sound of a predetermined acoustic musical instrument through a natural microphone simulation regardless of another sort of sound concurrently produced.
In accordance with one aspect of the present invention, there is provided a sound generating system associated with a musical instrument for producing a sound from vibrations generated in the musical instrument, and the sound generating system comprises a pickup unit attached to the musical instrument for converting the vibrations to a first electric signal, a signal receiving section connected to the pickup unit and outputting a second electric signal corresponding to the first electric signal, a data processing section connected to the signal receiving section, simulating a direct sound produced from the vibrations and at least a reverberation of an original sound directly generated from the musical instrument on the basis of the second electric signal and adding a signal component representative of the simulated reverberation to a signal component representative of the simulated direct sound for producing a third electric signal and a sound generating section connected to the data processing section and producing the sound approximate to the original sound from the third electric signal.